None of the three are recommended or sold by their respective companies for "off road use". All three have internally drilled and slotted axles as a part of their clockwork. I'm not sure what you have in mind and therefore not sure you'll be happy with 29'er service you'd get from any of them.

That said, unlike the other two, the Sturmey-Archer S-RK3 has factory twist, thumb, trigger, dual paddle, bar-end, and down tube shifters available and you can buy every individual internal part if you snarf it and need to repair.

One other choice would be Sturmey's CS-RK3. It's index shifted with any Shimano front derailleur mountain bike shifter and Sturmey claims you can gear it all the way down to 22x34.